One piece disposable threshold test can electrode for use with an implantable cardioverter defibrillator system

Abstract

The present invention is a one piece, disposable pulse generator emulator for emulating a subcutaneous implantable cardioverter defibrillator (ICD) having an active housing electrode. The emulator of the present invention is for use with an external test system to screen a patient for candidacy for an ICD by determining the patient's minimum defibrillation threshold voltage. The one piece, disposable emulator has a housing that has substantially the same conductive geometry as the desired implantable pulse generator.

We claim: 
     
       1. A one piece, disposable pulse generator emulator for emulating a subcutaneous pulse generator having a housing that forms an active housing electrode for use with a remote test system to screen a patient for candidacy for implantation of a desired pulse generator, the emulator comprising: an emulator housing having substantially the same conductive geometry as the desired implantable pulse generator;   a lead having proximal and distal ends, the proximal end being permanently, fixedly attached to the emulator housing; and   a test system connector permanently, fixedly attached to the distal end of the lead for connection to the remote test system:   such that the housing, the lead and the connector form a unitary device in which the housing and the lead are permanently secured to each other.   
     
     
       2. The emulator of claim 1 wherein the emulator housing has a length and a width substantially the same as that of the desired implantable pulse generator. 
     
     
       3. The emulator of claim 1 wherein the emulator housing is thinner than the desired implantable pulse generator. 
     
     
       4. The emulator of claim 1 wherein the emulator housing has a resistance of less than one ohm. 
     
     
       5. The emulator of claim 1 wherein the lead comprises a plurality of conductors having a sterilizable insulation sheath thereabout. 
     
     
       6. The emulator of claim 1 wherein the emulator housing has an upper flange, integral with the emulator housing and wherein the proximal end of the lead is connected to the emulator housing at the upper flange. 
     
     
       7. The emulator of claim 6 wherein the upper flange is substantially similar in size to a header on the desired pulse generator. 
     
     
       8. The emulator of claim 1 further comprising a jumper cable for electrically connecting the test system connector to the remote test system. 
     
     
       9. The emulator of claim 8 wherein the lead has a length of approximately 5 cm. 
     
     
       10. The emulator of claim 1 wherein the lead has a biocompatible insulation sheath for approximately 5 cm adjacent the proximal end and a non-biocompatible insulation sheath about the remainder of the lead. 
     
     
       11. An active housing emulation system comprising: an integral, disposable emulator housing and a lead unit wherein the housing forms an active electrode and has substantially the same conductive geometry as a desired implantable pulse generator, and wherein the lead unit has proximal and distal ends wherein the proximal end is permanently, fixedly attached to the housing such that the housing and the lead unit are permanently secured to each other;   an implantable electrode lead implantable in a desired permanent location of a patient's body; and   an external test system electrically connected to the distal end of the emulator housing lead unit and to the implantable electrode lead.   
     
     
       12. The emulator of claim 11 wherein the emulator housing has a length and a width substantially the same as that of the desired implantable pulse generator. 
     
     
       13. The emulator of claim 11 wherein the emulator housing is thinner than the desired implantable pulse generator. 
     
     
       14. The emulator of claim 11 wherein the emulator housing has a resistance of less than one ohm. 
     
     
       15. The emulator of claim 11 wherein the lead unit comprises a plurality of conductors having a sterilizable insulation sheath thereabout. 
     
     
       16. The emulator of claim 11 wherein the emulator housing has an upper flange, integral therewith and wherein the proximal end of the lead unit is connected to the emulator housing at the upper flange. 
     
     
       17. The emulator of claim 16 wherein the upper flange is substantially similar in size to a header on the desired pulse generator. 
     
     
       18. The emulator of claim 11 further comprising a jumper cable for electrically connecting the lead unit to the external test system. 
     
     
       19. The emulator of claim 18 wherein the lead has a length of approximately 5 cm. 
     
     
       20. The emulator of claim 11 wherein the lead has a biocompatible insulation sheath for approximately 5 cm adjacent the proximal end and a non-biocompatible insulation sheath about the remainder of the lead. 
     
     
       21. A method of screening a patient for candidacy for implantation of a desired pulse generator having an active housing electrode, the method including the steps of: (a) implanting a first conductive lead into the patient's body wherein the first conductive lead is intended to remain in place if the patient is fitted with the desired pulse generator;   (b) implanting a one piece, disposable pulse generator emulator into the pectoral region of the patient wherein the disposable pulse generator emulator has a second conductive lead fixedly attached thereto;   (c) providing an external test system which simulates operation of the desired pulse generator;   (d) electrically connecting the first conductive lead and the second conductive lead to the external test system;   (e) conducting the patient screening;   (f) disconnecting the first and second conductive leads from the external test system; and   (g) disposing of the one piece, disposable pulse generator emulator when the testing is complete.